Abstract
Background
Researchers recently investigated the effectiveness of virtual reality (VR) in helping children with cerebral palsy (CP) to improve motor function. A systematic review of randomized controlled trials (RCTs) using a meta-analytic method to examine the effectiveness of VR in children with CP was thus needed.Purpose
The purpose of this study was to update the current evidence about VR by systematically examining the research literature.Data Sources
A systematic literature search of PubMed, CINAHL, Cochrane Central Register of Controlled Trials, ERIC, PsycINFO, and Web of Science up to December 2016 was conducted.Study Selection
Studies with an RCT design, children with CP, comparisons of VR with other interventions, and movement-related outcomes were included.Data Extraction
A template was created to systematically code the demographic, methodological, and miscellaneous variables of each RCT. The Physiotherapy Evidence Database (PEDro) scale was used to evaluate the study quality. Effect size was computed and combined using meta-analysis software. Moderator analyses were also used to explain the heterogeneity of the effect sizes in all RCTs.Data Synthesis
. The literature search yielded 19 RCT studies with fair to good methodological quality. Overall, VR provided a large effect size (d = 0.861) when compared with other interventions. A large effect of VR on arm function (d = 0.835) and postural control (d = 1.003) and a medium effect on ambulation (d = 0.755) were also found. Only the VR type affected the overall VR effect: an engineer-built system was more effective than a commercial system.Limitations
The RCTs included in this study were of fair to good quality, had a high level of heterogeneity and small sample sizes, and used various intervention protocols.Conclusions
Then compared with other interventions, VR seems to be an effective intervention for improving motor function in children with CP.
Cerebral palsy (CP) is the leading cause of childhood physical disabilities, affecting around 2 to 3 children per 1,000 live births.1–3 CP is caused by damage to 1 or more areas of the developing brain which affect body movements, posture, and coordination.4 The symptoms of CP vary, but all individuals with CP have problems in motor function and are often accompanied by disturbances of sensation, perception, cognition and communication.3,4 The International Classification of Functioning, Disability and Health (ICF) model has been used extensively as a theoretical framework to understand the health-related outcomes of children with CP.5–7 For example, a child with CP may have impaired “body structure and function” (eg, spasticity, range of motion limitations, muscle weakness, impaired sensation and impaired coordination), limited “activity” (eg, difficulty in maintaining and changing body positions, unstable walking and moving around, poor fine motor function, and unable to perform activities of daily living), and restricted “participation” (eg, difficulty in engaging in sports activities with peers in school or other life situations).7 Moreover, environmental factors (eg, physical accessibility to a basketball court) that include accessibility, availability, opportunity, support, and attitudes of the settings where children live and personal factors (eg, age, motivation, priority and goals, CP type) are influential to the achievement of health and health-related outcomes (ie, body structure and function, activities, and participation) in children with CP.6,7 Consequently, a plan of care for children with CP should not only consider improving their impaired body structure and function, limited activity, restricted participation, but also changing environmental and personal factors to have an optimal effectiveness.6,7
Virtual reality (VR) (eg, Xbox Kinect [Microsoft, Redmond, Washington], Wii [Nintendo, Kyoto, Japan]) has recently been explored as an intervention to improve motor function in children with CP. Virtual reality is defined as “the use of interactive simulations created with computer hardware and software to present users with opportunities to engage in environments that appear to be and feel similar to real-world objects and events.”8 VR applications use interactive simulations that respond to a user’s movement such that a child can interact within a virtual environment while performing functional activities.9,10 Levac et al11 summarized several “active ingredients” (ie, attributes) that VR can provide to help children improve in rehabilitation: VR system and games create an exercise environment in which children can increase duration, intensity, and frequency of practice. VR can provide an ecologically valid environment that is similar to the real world so children can perform task-specific practices.11 In the virtual environment, task difficulty can be easily adjusted to provide sufficient challenge for a child while playing.11 It can also provide immediate visual and auditory feedback that is related to task performance or results.11 VR games can provide children opportunities for problem-solving through task-driven training to optimize motor learning, which can later lead to neuroplasticity changes.11 Because of the game features and animation, VR can increase children’s motivation and engagement during playing.11 Moreover, VR offers social play opportunity for participating in play situation, and increases support from family members, peers, teachers, and therapists.11 Therefore, through these attributes, VR can effectively improve the child’s impaired body structure and function (eg, improved range of motion, increased muscle strength) and decrease limited activity (eg, improving reaching ability, grasping function, or ambulation ability) as well as influence the child’s “personal factors” (eg, increased motivation and confidence).12,13 Moreover, virtual environments can directly shape the “environmental factors” by decreasing the environmental barriers (eg, ease task difficulty by decreasing the required range of motion of finger flexion), increasing the roles of the supportive persons from family, siblings, or friends (eg, decreasing personal assistance).11–13 The optimal goal of using VR intervention is to assist children in increasing their participation in the real-world environment by gradually overcoming and adapting all the possible environmental barriers via interaction in the virtual environment and transferring the learned skills to the real world.13 However, whether the learning occurred in the virtual environment can successfully transfer to real world is still inconclusive and depends on the user characteristics and contextual factors.13,14
Studies investigating effectiveness of VR in children with CP have shown some effect on improving ambulation, postural control, and arm function.15–19 In our previous meta-analysis,16 which included 3 randomized controlled trials (RCTs) and 11 case series that examined the effect of VR on arm function in children with CP, we found VR overall provided a strong effect size (d = 1.00) when comparing between post-VR and pre-VR interventions. When the outcome variables were further broken down according to the ICF model, a large effect was reported in participation (d = 1.92), a small effect on activity (d = 0.46), and a medium effect on body structure and function (d = 0.70).16 In addition, the subgroup analyses showed younger children receiving home or laboratory-based VR and using an engineer-built VR system had a better effect.16 Dewar et al18 examined the exercise interventions to improve postural control in children with CP and included 3 studies with level II and level III evidence20 that used VR as the intervention. This study showed a conflicting result regarding whether VR could enhance postural control in children with CP: 2 studies showed improvement in standing balance and 1 showed no improvement in functional standing balance.18 Bonnechère et al19 included 31 studies (7 RCTs, 16 cohort studies, and 8 single-case studies) to examine the effect of “serious gaming” (defined as games whose primary focus is not pure entertainment) in pediatric rehabilitation. The authors concluded it was difficult to compare the different studies because of the lack of standardized rehabilitation strategies and different clinical assessment tools.19 The latter 2 systematic reviews did not report the VR effect in different ICF components.
To the best of our knowledge, no systematic reviews using a meta-analytic method (ie, using statistical method to compute and combine data from multiple studies)21,22 to examine the effectiveness of VR in children with CP have ever been published, except for our own work in arm function. All these published systematic reviews included very few RCTs (3–7 RCTs only). At least 20 studies using RCT design have been published since the databases were accessed by the authors of the most recently published systematic reviews. Therefore, the 4 aims of this review were to examine the effect of VR in children with CP using a systematic review and meta-analytic approach by adding more RCTs and quantifying effect sizes (Cohen d); to classify outcome measures based on the ICF model; to group studies based on the movements the outcome measures of each study intended to evaluate (ie, arm function, postural control, and ambulation); and to identify the association between the VR effect and key characteristics of the child (eg, CP type, age) as well as aspects of the intervention protocol (eg, intervention setting, intervention dosage).
Methods
Data Sources and Searches
We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to conduct this review.23,24 Two authors (Y.C., H.D.F.) independently conducted systematic literature searches in December 2016, using the electronic databases: PubMed, CINAHL, Cochrane Central Register of Controlled Trials, ERIC, PsycINFO, and Web of Science, as well as a manual search of the reference lists of each article. Keywords or mesh terms (if applicable) used for the search included the following: virtual reality, virtual reality exposure therapy, virtual realities, virtual environment, computer game(s), Kinect, Wii, Playstation, videogame(s), active game(s), serious game(s); cerebral palsy, cerebral palsies, Little disease, infantile palsies, spastic diplegia(s), spastic diplegic, spastic hemiplegia(s), spastic hemiplegic, spastic quadriplegia(s), spastic quadriplegic; upper extremity, arm, upper limb, reach, grasp, grip, fine motor, gait, walking, leg, gross motor, ambulation, lower extremity, trunk, torso, posture, balance, postural control. An example of the search strategy used in PubMed is provided in the Appendix.
Study Selection
The 5 inclusion criteria for studies to be included in this systematic review/meta-analysis were as follows: participants in the study were children who had CP and were aged between birth and 21 years old; the study compared VR with a conventional therapy (eg, usual care) or control group (eg, no intervention); the outcome measures used in the study were related to motor function, such as arm function, walking, or postural control; the study design was an RCT or randomized cross-over design; and the study was written in English or Chinese. Studies were excluded if the study did not provide sufficient data to compute the effect size (eg, no standard deviations), or if the study was designed to compare the immediate response after being exposed to VR for a short period of time (eg, 60 minutes) without receiving a VR-related intervention in weeks.
Data Extraction and Quality Assessment
A meta-analysis coding template was created and used to code the demographic, methodological, and miscellaneous variables extracted from each RCT by following the methods suggested by Cooper and Hedges.21 Demographic data included children’s age, ethnicity, gender, diagnosis, severity, cognitive status, and other disabilities associated with the participants. Sample size, sampling method, type of movement investigated, VR type (eg, commercially available systems: Kinect, Wii), VR dosing (duration, intensity, length, total treatment duration), comparison therapy type, dosing in the comparison therapy, and instruments used to measure outcome variables were coded as methodological variables. Year of publication, name of the authors, country, and affiliation of the authors were included in the miscellaneous variables.
The quality of RCTs was evaluated using the Physiotherapy Evidence Database (PEDro scale).25 The PEDro scale includes 11 items with 1 item assessing the external validity and 10 items assessing the internal validity (including random allocation, concealment of allocation, baseline equivalence, blinding procedure, intention to treat analysis, adequacy of follow-up, between-group analysis, and consideration of data variability). A total of 10 points could be yielded from evaluating the internal validity of each study, with scores of 9 to 10 representing “methodologically excellent,” 6 to 8 representing “good,” 4 to 5 representing “fair,” and less than 4 representing “poor.”26
Relevant information from the included studies was extracted and coded by the same author (Y.C.). A second reviewer (H.D.F.) checked all the extracted data. Any discrepancies were resolved by discussion in order to reach a consensus.
